Add the ability to download messages by product reference

[v-kolesnikov]

Add an ability to download messages that includes product with the given reference.
It might be a simple button that returns ZIP-file with messages.

Input:

# 20190806T081541Z.xml
<ONIXMessage xmlns="http://ns.editeur.org/onix/3.0/reference" release="3.0">
  <Header>
    <SentDateTime>20190806T081541Z</SentDateTime>
  </Header>
  <Product>
    <RecordReference>1</RecordReference>
  </Product>
  <Product>
    <RecordReference>2</RecordReference>
  </Product>
  ...
</ONIXMessage>

# 20190807T081541Z.xml
<ONIXMessage xmlns="http://ns.editeur.org/onix/3.0/reference" release="3.0">
  <Header>
    <SentDateTime>20190807T081541Z</SentDateTime>
  </Header>
  <Product>
    <RecordReference>1</RecordReference>
  </Product>
  <Product>
    <RecordReference>2</RecordReference>
  </Product>
  ...
</ONIXMessage>

Output (by ref 1):

# 20190806T081541Z.xml
<ONIXMessage xmlns="http://ns.editeur.org/onix/3.0/reference" release="3.0">
  <Header>
    <SentDateTime>20190806T081541Z</SentDateTime>
  </Header>
  <Product>
    <RecordReference>2</RecordReference>
  </Product>
</ONIXMessage>

# 20190807T081541Z.xml
<ONIXMessage xmlns="http://ns.editeur.org/onix/3.0/reference" release="3.0">
  <Header>
    <SentDateTime>20190807T081541Z</SentDateTime>
  </Header>
  <Product>
    <RecordReference>1</RecordReference>
  </Product>
</ONIXMessage>